What was is like?
That depended who you were. Many people went on the crusade because they had no real future in Europe. Amonst the noble man only the oldest son was the heir of his father. Younger sons had virtually little chance in life. Best thing that could happen was that they became powerful/ rich by fighting in a duell or a battle. For these hopeless the crusade was a real chance.
Other than nobleman many common people attendet the crusade, as servants or because the had little else to do and no other hope to gain social status, were promised that they would go to heaven if they died,... Little is known about the life of these man and woman because they could not read and write and for the writers of history they were not important.

It was expected that crusaders themselfes cared about everything they needed and they also had to pay themself if they wanted to rent a ship to cross the sea. (Of course the king cared for the people under his command - would have been stupid if he had not done that).

People took care of their needs by trade, buglary of whatever. Anyone who was not catholic was an okay target, and if a catholic did not supported the crusaders there were always ways to convince him (tell him he would go to hell).

Did a lot of people die?? Yes. I do not know if there is any way to answer how many. No population records were made. Writers always lied about the losses in battle to prove how sucessfull own army was.

Culture shock: Hell yes! Europe: Little knowledge about anything, believe that bathing will be bad for health, many illiterate people. Jerusalem: knowledge saved and developed since antiquity, brightest minds of the world united there, people caring about appearance,...